1. Field of the Invention
This invention relates generally to communication systems, and more particularly to a context aware call processing architecture for effecting user-defined features.
2. Description of the Prior Art
Traditional telephony features are standardized and coarse grained. Users are given access to a plurality of features (Call Forward on Busy etc.) that are centrally located within a communication system, such as a PBX.
The utility of these features is limited by their inability to be personalized to the needs of an individual and to be aware of the user's current activities. For example, a user may be occupied with some work. Such a user will therefore be ‘busy’ in relation to other work of less importance but ‘available’ in relation to work of higher priority or to information about his/her current task. Traditional telephony features such as Call Forward on Busy are coarse-grained and therefore cannot match these important human distinctions.
The very limited degree of personalization in feature sets according to the prior art results from the fact that traditional call processing has relied on a centralized definition of common features to accelerate the time to market and to improve system stability. Expert designers typically develop standard features that are tested for compatibility before deployment. Personalization with such a scheme is impossible because of the large numbers of possible personalized features.
The Internet telephony work on the SIP protocol (IETF) has created the CPL standard that partially addresses the goal of achieving personalized features (see Sinnreich, H; Johnston, A. B., Internet Communication Using SIP, Wiley, 2001 pp 104-108, and The Internet Draft by Schulzrinne, H.; Rosenberg, J.; SIP Caller Preferences and Callee Capabilities, draft-ietf-sip-callerprefs-05.txt available at: http://www.softarmor.com/sipwg/drafts/draft-ietf-sip-callerprefs-05.txt). Although CPL allows the user a limited ability to locally specify call handling, it does not go beyond specifying policies on call handling based on the identity of the incoming caller and time of day. It does not take into account the user's context and is unable to accommodate conflict handling between user policies, thereby severely limiting the utility of CPL, it's scalability and evolvability.